Process for preparing a food product using depolymerised pectin as stabiliser

ABSTRACT

The present invention provides a process for the production of a food product comprising the steps of (i) contacting a food material with a stabilizer to provide a food intermediate; and (ii) fermenting the food intermediate; wherein the stabilizer comprises a depolymerized pectin and wherein the food material comprises a protein.

This application is the U.S. national phase of international applicationPCT/IB2004/002795 filed 19 Aug. 2004, which designated the U.S., andclaims priority to GB 0319503.9 filed 19 Aug. 2003, the entire contentof each of which is hereby incorporated by reference.

The present invention relates to a process for the production of a foodproduct and to a food product produced by the process.

BACKGROUND ART

Certain protein-containing food products, such as acidified dairyproducts like drinking yoghurt and stirred yoghurt, require a stabiliserto stabilise the protein system against aggregation, sedimentation andseparation. The major protein present in cows' milk is casein, whichconstitutes about 80% of the total protein content. The remainingprotein in cows' milk is termed “whey protein” and consistspredominantly of beta-lactoglobulin and alpha-lactalbumin. Cows' milk iscomprised of water and milk solids. The milk solids include fat and milksolid non-fat (MSNF) which is made up of protein together with lactoseand various minerals.

Pectin has traditionally been used as a stabiliser in protein-containingfood products such as acidified protein beverages (typically high esterpectin) and stirred yoghurt (typically low ester pectin). Pectin is astructural polysaccharide found in green land plants, for example, fruitand vegetables and may be extracted from citrus fruit peel. At amolecular level, pectin consists of a linear chain of galacturonic acidunits linked through α-1,4 glycosidic bonds (the ‘smooth region’). Thisregular structure is interrupted by rhamnopyranosyl residues with sidechains of neutral sugars (the ‘hairy region’). Pectin molecules have amolecular weight of up to about 200,000 and a degree of polymerisationof up to about 800 units. A proportion of the carboxylic acid groups ofthe galacturonic acid units are methyl esterified. The properties ofpectin depend on the degree of esterification, which is less than 50%for low-ester (LE) pectin and more than 50% for high-ester (HE) pectin.

Pectin is known to have the ability either to prevent aggregation ofcasein micelles or to be the cause of it, depending on the pH of thesystem. The micellar casein-pectin system switches from hydrocolloidnon-adsorption and depletion flocculation at neutral pH 6.7 tohydrocolloid adsorption and polymeric stabilisation at pH 4 [2, 4].Therefore, although pectin is an effective stabiliser at acidic pH, atneutral pH conditons it is incompatible with the milk proteins andseparates the milk into two phases.

Depletion flocculation of casein micelles involves exclusion of thepolymer pectin chains from the space between the colloidal caseinmicelles, which induces an attractive interaction between the caseinmicelles. If the depletion attraction is strong enough, segregativephase separation occurs resulting in two immiscible aqueous phases,where the upper phase is rich in pectin and poor in casein micelles,while the lower phase is, on the contrary, mainly loaded with caseinmicelles [1, 2, 4]. At a low pectin concentration, the phase volumeoccupied by the pectin molecules is low. At increasing pectinconcentrations, the occupied volume and the osmotic pressure of thepectin solution increase, which induces a stronger flocculation of thecasein micelles. Finally, at a certain pectin concentration, the phaseseparation takes place. About 0.20% HE pectin is needed to induce phaseseparation in skimmed milk at pH 6.7 [2].

Pectin is a non-adsorbing polymer when it is in solution with skimmedmilk at pH 6.7, but when lowering the pH to 5.3, the pectin moleculeadsorbs onto the casein micelle. If the pectin concentration is low andinsufficient for full coverage of the casein micelles, bridgingflocculation occurs. When increasing the pectin concentration further,the casein micelles become fully coated and the system re-stabilises.Thereby, the attraction between the casein particles is lowered andstable conditions are obtained [2]. Although the adsorption of pectinonto the casein micelles is possible at pH conditions above theisoelectric point of caseins (pI˜4.6), the pH of efficient stabilisationis generally restricted to about pH 3.5 to 4.4 where the pectin andcasein carry sufficient opposite net charges for effective adsorption[4].

This mechanism is used to stabilise acidic protein beverages againstprotein aggregation. Efficient polymeric stabilisation is achieved bythe combination of high molecular weight, high surface coverage and ablockwise distribution of galacturonic acid groups. Therefore in theory,the best polymeric stabiliser would be a copolymer with a stronglyadsorbing terminal with low solvent affinity and a voluminous danglingend with high solvent affinity to increase repulsion upon forced polymeroverlap [4]. For stabilisation of acidic protein beverages, HE pectinhas generally been considered to be the hydrocolloid of choice. AlthoughHE pectin has a lower charge density than low-ester (LE) pectin andthereby a weaker electrostatic interaction with casein micelles, itgenerally serves as a more effective stabiliser of casein dispersions.It is believed that a smaller region of the HE pectin molecule interactswith the casein particle, allowing a more substantial part of the pectindangling chain to be freed from solvent interaction thus preventingprotein aggregation through steric hindrance [7].

The difference in the stabilisation characteristics of HE pectin atdifferent pH values determines the applications in which HE pectin maybe used as a stabiliser and the stage in the production process when theHE pectin may be added.

The acidification of protein beverages can be achieved by the additionof an acid (for example an acidic fruit juice). Acidification can alsobe achieved via fermentation. However, for acidified protein beveragescontaining HE pectin, these two processes are technically distinct fromeach other:

For directly acidified protein beverages like milk juice drinks,addition of juice and/or acid directly to milk results in the formationof acid casein particles of uncontrollable size. These particles aretypically too big to be kept in suspension resulting in a non-stableacidic protein beverage with a sandy mouth-feel upon heat treatment. Inthe production of directly acidified protein beverages, thedestabilising effect of high molecular weight HE pectin at neutral pH isused to advantage. The HE pectin is typically added to the milk beforeacidification and, under the neutral pH conditons, induces separation ofthe milk into two phases. The osmotic effect of pectin concentrates theintact casein micelles in a lower, protein rich phase and leaves thepectin-rich whey phase virtually free of micelles. The casein phase hasthe properties of a liquid and can be dispersed into the whey phase inthe form of droplets by stirring. The more shear applied to the system,the smaller the drops become and the more like an oil-in-water emulsionthe system becomes. The subsequent rapid pH drop through directacidification freezes the casein droplets in their native form at thesize they had in the neutral milk and thereby creates acid caseinparticles of controlled size [5]. During the acidification processnatural stabilisation of casein is destroyed and the presence of HEpectin that forms the above-mentioned protective coat around the caseinmicelles prevents aggregation and precipitation [13].

Thus, for directly acidified protein beverages, HE pectin is added atneutral pH and induces phase separation. Strong mechanical stirring isthen used to keep the precipitated casein proteins in suspension. Thesystem is rapidly acidified freezing the casein proteins in suspension.The casein proteins are stabilised by the high-ester pectin moleculesunder the acidic conditions and are thereby prevented from sedimentationin the final application.

For fermented milk products, HE pectin cannot be used in the same way.Production of fermented milk products typically involves the steps ofpasteurisation of the milk base, followed by inoculation with bacteriaand finally fermentation. During fermentation by bacteria, the pH of themilk is reduced gradually and slowly in contrast to the rapid pH drop inthe above application. Thereby, a disintegration of the casein micellestakes place that thickens or gels the milk into yoghurt [5, 13].

Addition of traditional, high molecular weight HE pectin to the milkbefore fermentation would induce phase separation as described above,when applied in concentrations required for efficient proteinstabilisation of the final fermented drink. Phase separation in thisapplication would be undesirable because the characteristic yoghurtstructure and its subsequent texture impact would be lost. Furthermorethe precipitated casein micelles cannot be kept in suspension bystirring in this application. Mechanical stress and incorporation ofoxygen is normally avoided during fermentation of milk to give the livebacteria the best fermentation conditions. Therefore, strong mechanicalstirring to keep the separated casein micelles in suspension cannot beapplied. Moreover, the pH drops too slowly to freeze the caseinstructures. In summary, high molecular weight HE pectin is not typicallyeffective if added to milk before fermentation and is instead addedafter fermentation to protect the acidified proteins against aggregation[14].

For fermented milk products like stirred yoghurt the typical choice ofpectin stabiliser is LE pectin that provides both stability and textureto the fermented protein system. In neutral milk the phase separationboundary is obtained at even lower pectin concentrations when LE pectinis applied [16]. In practice about 0.15% LE pectin can be added toneutral milk without phase separation. However, this low dosage is oftennot sufficient to obtain a required high viscosity and creaminess in theresulting fermented milk product like stirred yoghurt. Moreover, therequest for improved viscosity and creaminess becomes even more relevantwhen the solid milk ingredients like proteins and fat are reduced in theformulation for the purposes of cost reduction or calorie reduction.

For fermented dairy products which contain live culture the finalproduct is not typically pasteurised or sterilised. It is therefore ofutmost importance to pasteurise the milk prior to fermentation, to avoidcontamination during fermentation and contamination of the finalproduct. When pectin is applied to fermented milk drinks containing liveculture, it must be sterilised as well to avoid contamination of theproduct. As discussed above, known commercial pectin products cannot beadded to the milk prior to pasteurisation, inoculation and fermentationand therefore the pectin needs to be sterilised separately. Thistypically involves the heat sterilisation of aqueous pectin solutionsthat require additional processing and equipment to both dissolve andheat the pectin. The pectin is typically in the form of a pectin syrupwhich is sterilised by heating and subsequently added to the alreadyfermented milk base. The additional pectin sterilisation processrequires additional tank capacity and heat equipment and increases theenergy costs. The alternative and much simpler method of adding pectindirectly to the fermented milk in the form of a dry mix with sugar isnot applicable due to the contamination risk.

For manufacturers of fermented milk products it would be easier andcheaper (e.g. in terms of process equipment and energy requirement) tooperate with a stabiliser which can be added to the milk prior tofermentation i.e. before the slow acidification. Before fermentation, itis common to pasteurise the milk in order to avoid contamination butalso, which is of significant importance, to heat denature the wheyproteins to get optimal yoghurt structure. This process would be greatlysimplified if the pasteurisation of milk could be combined with thepasteurisation of the stabiliser. The stabiliser would then not have tobe sterilised separately. Additionally, the method of addition of thestabiliser would be more flexible, since both direct addition as dry mixwith sugar and dispersion in a saturated sugar solution could be used asalternatives to the dissolved stabiliser solution.

It is desirable to seek a stabiliser of fermented protein food productsthat is compatible with proteins in the food material such as milk andwhich can be added to the food material, resist a pasteurisationtogether with the food material, prevent flocculation and phaseseparation during fermentation and finally stabilise the acidifiedproteins after fermentation and optionally after a final pasteurisationto prolong the shelf-life.

One of the difficulties in providing a stabiliser that may be addedprior to pasteurisation, inoculation and fermentation is incompatibilityof the stabiliser with the proteins (e.g. milk proteins) at neutral pH.Generally, proteins (e.g. milk proteins) and polysaccharides (e.g.pectin) are incompatible at a sufficiently high bulk concentration andunder conditions inhibiting formation of inter-biopolymer complexes.This mainly occurs at a sufficiently high ionic strength (exceeding0.2), pH values above the protein isoelectric point and at a totalbiopolymer concentration above 3-4% [1, 12, 16], whereas alkaline pHconditions and low ionic strengths enhance the co-solubility [1, 4].Furthermore, protein-polysaccharide incompatibility usually increases onheating and with protein denaturation [6, 9, 12, 15]. Therefore, theimportant pasteurisation of milk, in order to denature the whey proteinsbefore fermentation, would be likely to enhance incompatibility evenfurther in a blend of casein micelles and pectin at neutral pHconditions. The conditions for a limited compatibility are different forsystems including neutral (e.g. locust bean gum and guar gum), sulphated(e.g. carrageenan) or carboxylated (e.g. pectin) polysaccharides and thecompatibility typically decreases in the ordersulphated>neutral>carboxylated polysaccharides [6, 7, 12]. The effect ofseveral hydrocolloids on the stabilisation of casein micelles has beentested with locust bean gum and guar gum of the neutral polysaccharides;gum arabic, CMC (carboxymethylcellulose), pectin, hyaluronic acid andalginates of the carboxylated polysaccharides; and agarose, heparin,chondroitin sulphates, cellulose sulphate, fucoidan and carrageenan ofthe sulphated polysaccharides. Only carrageenan induced significantstabilisation at pH 6.8 [11].

High molecular weight and rigidity of macromolecule chains tend toincrease incompatibility and normally, linear polysaccharides are moreincompatible with proteins than branched polysaccharides. In general,the larger the difference in molecular weight and in hydrophilicity, themore pronounced the incompatibility of the biopolymers [12]. Thefollowing examples are found in literature:

-   -   A system of HE pectin and skimmed milk at natural pH clearly        demonstrates depletion flocculation [1, 4, 8]. The        destabilisation and subsequent phase separation is even known as        a tool to efficiently concentrate proteins from skimmed milk on        a technological scale [10]. Depletion flocculation of casein        micelles at neutral pH occurs whatever the type of pectin used        (low-ester, low-ester amidated and high-ester pectin). The phase        separation boundary is obtained at lower polysaccharide        concentrations with LE pectin than for HE pectin [16].    -   Mixing guar gum (neutral polysaccharide) with skimmed milk at        neutral pH leads to phase separation, but the phase boundary        shifts to higher guar concentrations, when the molecular weight        of guar gum is reduced through degradation [17]. Locust bean        gum, guar gum and hydrolysed guar gum with reduced molecular        weight (all neutral polysaccharides) behave differently in a        micellar casein system at neutral pH. Since locust bean gum and        hydrolysed guar gum have a lower intrinsic viscosity than the        initial guar gum sample, they occupy a smaller volume in the        medium per molecule than the guar gum chains. The exclusion of        the polymer thus occurs to a lesser extent, resulting in a        decreased aggregation of casein micelles at the same        polysaccharide concentration [18].    -   At pH 7, CMC readily precipitates casein from both skimmed milk        and from casein model solutions. Less CMC is required when        higher viscosity types are used, i.e. types with higher        molecular weight [4].

At present, the only well-known and readily available commercial producton the market for fermented protein beverage applications which can beadded prior to fermentation is soluble soybean polysaccharide (SSPS),produced by Fuji Oil [19]. SSPS is a water-soluble polysaccharideextracted and refined from soybean. Fuji Oil Co., Ltd., Japan, hasmarketed SSPS under the brand name SOYAFIBE-S since 1993. SSPS is mainlycomposed of the dietary fibre of soybean and has relatively lowviscosity and high stability in aqueous solution.

SSPS is a much more branched polymer than HE pectin with a rather shortbackbone and many more long side chains. HE pectin has a long backboneand just a few short side chains. The component sugars in SSPS aremainly galactose, arabinose, galacturonic acid but also include manyothers such as rhamnose, fucose, xylose and glucose. Gel filtrationchromatographic analysis by HPLC shows that SSPS consist roughly ofthree components having approximate molecular weights of 550,000; 25,000and 5,000. The major component of SSPS consists of long-chainrhamnogalacturonan and short-chain homogalacturonan, while citrus pectinconsists of short-chain rhamnogalacturonan and long-chainhomogalacturonan. For SSPS, homogenous galactosyl and arabinosyl neutralsugar side chains combine with the rhamnogalacturonan region throughrhamnose and are longer than the galacturonosyl main backbone.

SSPS has a galacturonic acid content of about 20% [19] whereas pectinhas a galacturonic acid content of at least 65%. The anion group of thisacid probably binds to the surface of cationic protein particles so thatSSPS protects the casein micelles. It is assumed that the adsorbed layerof SSPS is thick, because each molecule is rich in side chains ofgalactose and arabinose [19]. SSPS is soluble in both cold and hot waterwithout gelation and shows a relatively low viscosity compared to theviscosity of other gums/stabilisers. Acid, heat or salts (e.g. Ca-salts)do not significantly affect the viscosity of SSPS in solution. Underacidic conditions, SSPS prevents protein particles from aggregation andprecipitation.

Unlike HE pectin, the point of interest with SSPS is its ability tostabilise protein particles at low pH conditions without raising theviscosity of the acidified protein beverage. SSPS is reported to performeven if applied at an early stage of processing before fermentation,which allows the manufacturing process to be improved. SSPS shows goodstabilising effect in lower pH products (below pH4.0). However, SSPS isless effective than HE pectin at higher pH such as around pH4.4 and/orhigh milk solid non-fat (MSNF) contents.

The need exists to provide alternative stabilisers which may be addedduring the production of fermented protein products prior tofermentation and preferably prior to the initial pasteurisation.

The present invention alleviates the problems of the prior art.

Statement of Invention

In one aspect the present invention provides a process for theproduction of a food product comprising the steps of (i) contacting afood material with a stabiliser to provide a food intermediate; and (ii)fermenting the food intermediate; wherein the stabiliser comprises adepolymerised pectin and wherein the food material comprises a protein.

In one aspect, the present invention provides a process for theproduction of a food product comprising the step of dissolving astabiliser directly in a food material wherein the stabiliser comprisesa depolymerised pectin and wherein the food material comprises aprotein.

In another aspect, the present invention provides a food productobtained or obtainable by the process of the present invention.

In a further aspect, the present invention provides use of a stabiliserfor improving the texture and/or viscosity of a food product, whereinthe stabiliser comprises a depolymerised pectin.

The term “food products” as used herein means a substance that issuitable for human or animal consumption. It will be readily understoodthat whilst the food product is the product of the process as hereindescribed, it may undergo further processing prior to consumption.

The term “stabiliser” as used herein means a substance which is capableof stabilising protein in a system with which it is contacted—so as toprevent or substantially reduce aggregation and/or sedimentation and/orseparation. The “system” may, for example, be a food material comprisinga protein, a food intermediate comprising a protein or a food productcomprising a protein. Preferably the “system” is a food productcomprising a protein.

The term “food material” as used herein means one or more ingredients ofthe food product.

The term “fermenting” as used herein typically means a process in whichdesirable chemical changes are brought about in an organic substratethrough the action of microbes and/or microbial enzymes. The fermentingconditions typically include attaining and maintaining a specifiedtemperature for a specified period of time. It will be readilyappreciated that the temperature and duration may be selected in orderto enable the biochemical processes associated with fermentation,especially the breakdown of organic compounds by micro-organisms toprogress to a desired extent. The organic compounds may, for example, becarbohydrates, especially sugars such as lactose.

The term “depolymerised pectin” as used herein means a substanceobtained or obtainable from naturally-occurring pectin by breaking itdown into two or more fragments. Pectin has a backbone comprisingrepeated structural units and typically has a degree of polymerisationof up to 800 units. These repeated structural units are principallygalacturonic acid residues and rhamnopyranosyl residues. Thedepolymerised pectin has chains of no greater than 250 units, such aschains of 15 to 250 units. Typically these units are galacturonic acidunits. The naturally-occurring pectin may be broken down by any suitabledepolymerisation method, such as various mechanical, chemical, thermal,enzymatic or irradiative methods or combinations of the same. Suitabledepolymerisation methods include those discussed in Studies on PectinDegradation, W. H. Van Deventer-Schriemer and W. Pilnik, ActaAlimentaria, vol. 16 (2), pp. 143-153 (1987). The term “depolymerisedpectin” also includes those substances, for example naturally-occurringsubstances, which have short chains of 15 to 250 units and in particularshort galacturonan chains of 15 to 250 galacturonic acid units.

Advantages

We have surprisingly found that a stabiliser comprising a depolymerisedpectin can be applied directly to a protein-containing food material,such as milk, prior to fermentation and yet stabilise the resultant foodproduct which may, for example, be a fermented dairy product.

Prior art stabilisers such as high molecular weight pectin induce phaseseparation if added to protein-containing food materials such as milkprior to fermentation. Therefore traditionally it has been necessary toadd a stabiliser after fermentation in order to achieve the desiredstabilisation of the food product.

A further advantage is that the method of addition of the stabiliser ismore flexible, since both direct addition as dry mix with sugar anddispersion in a saturated sugar solution may be used as alternatives tothe dissolved stabiliser solution.

We have also surprisingly found that a stabiliser comprising adepolymerised pectin dissolves more easily directly in a food materialsuch as milk than other stabilisers such as pectin. The presentstabiliser may therefore be dissolved directly in the food materialavoiding the need for a separate dissolution step. This furthersimplifies the production process.

For ease of reference, these and further aspects of the presentinvention are now discussed under appropriate section headings. However,the teachings under each section are not necessarily limited to eachparticular section.

Preferred Embodiments

Process

As previously mentioned, in one aspect the present invention provides aprocess for the production of a food product comprising the steps of (i)contacting a food material with a stabiliser to provide a foodintermediate; and (ii) fermenting the food intermediate; wherein thestabiliser comprises a depolymerised pectin and wherein the foodmaterial comprises a protein.

In one aspect, the present invention provides a process furthercomprising, before step (ii), the step of (i)(a) pasteurising the foodintermediate. In other words, the present invention provides a processfor the production of a food product comprising, in the following order,the steps of (i) contacting a food material with a stabiliser to providea food intermediate; (i)(a) pasteurising the food intermediate; and (ii)fermenting the food intermediate; wherein the stabiliser comprises adepolymerised pectin and wherein the food material comprises a protein.

The term “pasteurising” as used herein means reducing or eliminating thepresence of live organisms (for example, microorganisms) within the foodmaterial. Preferably, pasteurisation is attained by maintaining aspecified temperature for a specified period of time. The specifiedtemperature is usually attained by heating. It will be readilyappreciated that the temperature and duration may be selected in orderto kill or inactivate certain bacteria, such as harmful bacteria. Arapid cooling step may follow.

We have surprisingly found that a stabiliser comprising a depolymerisedpectin can be applied directly to a protein-containing food material,such as milk, prior to pasteurisation and fermentation and yet stabilisethe resultant food product which may, for example, be a fermented dairyproduct.

This embodiment of the present invention is particularly advantageouswhen the food product does not undergo a final pasteurisation step, forexample because it comprises a live culture. In applications such asthese, this process allows the manufacturer of the food product to avoidseparate pasteurisation of the stabiliser since the stabiliser and thefood material may be pasteurised together prior to fermentation. Thisleads to benefits in terms of lower energy and equipment costs, reducedprocessing time and a simplified processing procedure. In particular theenergy costs, tank capacity and heat equipment associated with theseparate pasteurisation of the stabiliser are not required.

In one aspect, the present invention provides a process furthercomprising, before step (ii), the step of (i)(b) inoculating the foodintermediate.

The term “inoculating” as used herein means introducing a micro-organisminto a system. The micro-organism may, for example, be a bacterium andmay be used to start a culture.

According to this aspect, the present invention may provide a processfor the production of a food product comprising, in the following order,the steps of (i) contacting a food material with a stabiliser to providea food intermediate; (i)(b) inoculating the food intermediate; and (ii)fermenting the food intermediate; wherein the stabiliser comprises adepolymerised pectin and wherein the food material comprises a protein.

In a highly preferred aspect, the present invention provides a processfor the production of a food product comprising, in the following order,the steps of (i) contacting a food material with a stabiliser to providea food intermediate; (i)(a) pasteurising the food intermediate; (i)(b)inoculating the food intermediate; and (ii) fermenting the foodintermediate.

In a preferred aspect, the process further comprises the step of (iii)pasteurising the product of step (ii).

In another preferred aspect, the process further comprises the step of(iv) adding juice and/or acid to the product of step (i)(b) and/or tothe product of step (ii) and/or to the product of step (iii).

Stabiliser

As previously mentioned, the stabiliser for use in the present inventioncomprises a depolymerised pectin.

In a preferred aspect, the depolymerised pectin has a viscosity at 25°C. in a 5% solution of 15 to 400 cP, such as 20 to 300 cP, 20 to 200 cP,20 to 100 cP or 25 to 50 cP. Typically the viscosity is measurable inaccordance with the method described below.

In one preferred aspect, the stabiliser has a viscosity at 25° C. in a5% solution of greater than 150 cP, such as greater than 150 cP to 400cP, for example greater than 150 cP to 300 cP or greater than 150 cP to200 cP. Typically the viscosity is measurable in accordance with themethod described below.

Preferably the depolymerised pectin is an essentially linearcarbohydrate polymer. This is in direct contrast to SSPS which is anessentially branched carbohydrate polymer.

The term “carbohydrate polymer” as used herein means a moleculecomprising substantially only carbon, hydrogen and oxygen atoms andwhich comprises repeated structural units of carboxylated polyhydroxyaldehydes. Preferably at least 90% of the atoms in the carbohydratepolymer are carbon, hydrogen or oxygen atoms, more preferably at least98%, such as 99% or 100%.

The carbohydrate polymer may comprise a main backbone substituted withone or more side chains.

The term “essentially linear” means that the total number of atoms inthe backbone is greater than the total number of atoms in the sidechains.

As previously mentioned, the depolymerised pectin comprises no greaterthan 250 repeated structural units. Preferably the depolymerised pectincomprises 15 to 250 units, such as 15 to 200 units, 20 to 150 units or30 to 100 units. Preferably the repeated structural units aregalacturonic acid residues and/or rhamnopyranosyl residues.

In one aspect, the depolymerised pectin comprises no greater than 250galacturonic acid units. Preferably the depolymerised pectin comprises15 to 250 galacturonic acid units, such as 15 to 200 galacturonic acidunits, 20 to 150 galacturonic acid units, or 30 to 100 galacturonic acidunits. In a preferred aspect, the depolymerised pectin has agalacturonic acid content of at least 65%, such as at least 70% or atleast 75% or at least 80%. The galacturonic acid content may be measuredusing the method described in [3].

In one aspect, preferably the depolymerised pectin has a degree ofesterification of at least 50%, such as at least 60%, or at least 65%.In this aspect, preferably the depolymerised pectin has a degree ofesterification from 50 to 90% such as from 50 to 85%, more preferablyfrom 65 to 75%. In a highly preferred embodiment the depolymerisedpectin has a degree of esterification of about 70%. Such depolymerisedpectins are hereinafter referred to as “high ester depolymerisedpectins”. Thus, in one preferred embodiment, the depolymerised pectin isa high ester depolymerised pectin (HE-DPP).

A depolymerised pectin having a degree of esterification at least 50%may be particularly advantageous in a process for the production of ayoghurt, especially a yoghurt beverage, although for a yoghurt a degreeof esterification below 50% may also be suitable.

In another aspect, preferably the depolymerised pectin has a degree ofesterification of less than 50%, for example, less than 40% or less than30% or less than 20%. Such depolymerised pectins are hereinafterreferred to as “low ester depolymerised pectins”. Thus, in one preferredembodiment, the depolymerised pectin is a low ester depolymerised pectin(LE-DPP).

In one particularly preferred embodiment of the invention, for example astirred yoghurt, the depolymerised pectin has a degree of esterificationof from about 20% to about 50%, more preferably about 30% to about 50%,more preferably still, from 40% to about 50%.

Depolymerised pectins with varying degree of esterification can beprepared by partial chemical or enzymatic deesterification of anydepolymerised pectin or pectic product. The chemical deesterificationreactions [20, 21] involve the acidic hydrolysis of methyl ester groupsin aqueous or partially aqueous medium by the use of organic or mineralacids, or the basic hydrolysis of methyl ester groups in aqueous orpartially aqueous medium by alkali metal or alkaline earth metalhydroxides, carbonates or strong bases such as ammonia or substitutedamines. The enzymatic deesterification of depolymerised pectin can beachieved by the use of plant pectinesterase, fungal pectinesterase orbacterial pectinesterase or combinations of these at pH, temperature andionic strength, that are compatible with the working conditions of theenzyme [24, 25].

The deesterification reactions can be carried out chemically orenzymatically on moistened depolymerised pectin raw material, crudepectin extracts, pectin concentrates or on precipitated pectin orpartially dried pectin as well as re-dissolved pectin, suspended pectinor partially dissolved or moistened pectin.

In another aspect of the invention the depolymerisation process can beone of or a combination of the below-mentioned depolymerisationprocesses used after or simultaneously with the deesterification of thepectin or pectic product by one of the above-mentioned deesterificationmethods.

A “pectic product” is defined as any form of pectin or modified pectinas it occurs in plant, pectin raw materials, and pectin processingstreams or isolated pectin products.

In one preferred embodiment of the invention, the depolymerised pectinis amidated.

Depolymerised amidated pectins with varying degree of amidation can beprepared by treating any depolymerised pectin or pectic product insolution, suspension or as a moistened product with ammonia water orgaseous ammonia at suitable ammonia concentration, temperature and timeto give a predetermined degree of amidation [22, 23]. Depolymerisationby the processes described hereinafter can be carried out during orafter amidation of pectin. Often it is convenient to obtain both a lowerdegree of esterification and a partial amidation in the samedepolymerised pectin product by carrying out one of the above mentioneddeesterification process before, during or after the amidation process.

A depolymerised pectin having degree of amidation less than 25%, such asless than 20% or less than 10% or less than 5% may be advantageous insome aspects.

Thus, in one particularly preferred embodiment, the depolymerised pectinis amidated LE depolymerised pectin.

In another particularly preferred embodiment, the depolymerised pectinis amidated HE depolymerised pectin.

The depolymerised pectin may be prepared from pectin by any suitabledepolymerisation method and the pectin may be obtained from any suitablesource. Examples of sources of pectin are citrus fruits (lemon, lime,orange, grapefruit, mandarine, tangarine, pommelo etc.) apple, sugarbeetroot, carrot, sunflower head residue, onion, peach, grape berry, mango,guava, squash, pumpkin, tomato, apricot, banana, bean and potato. Thepectin may be a commercially available pectin. In one aspect, thedepolymerised pectin is obtainable, preferably obtained from citrusfruits.

Alternatively, the depolymerised pectin may be prepared from one of thesources of pectin directly, without first isolating the pectin, and thedepolymerised pectin may subsequently be extracted. For example, thedepolymerisation of pectin can be carried out in harvested plantmaterial, after processing of plant material, for example in plantresidues from juice production before or after drying. Thedepolymerisation can also be carried out during pectin processing:before the pectin extraction, during pectin extraction or in the pectinjuice or concentrate after the pectin extraction. It is also possible tocarry out the depolymerisation in wet precipitated pectin, during dryingof pectin or in dry pectin after the pectin has been isolated forexample, in dry pectin, moistened pectin, dissolved pectin or suspendedpectin.

Depolymerisation methods include various mechanical, chemical, thermal,enzymatic and irradiative methods or combinations of any thereof, inparticular those methods capable of breaking down long chains such aslong galacturonan chains into shorter chains, for example into chains of15 to 100 repeated structural units such as galacturonic acid units.

The chemical depolymerisation methods could be acid, alkaline, oxidativeor reductive methods. Acid depolymerisation is shown in Mazoyer et al.UK Patent Application GB 2,311,024 (1997). Alkaline depolymerisation ofpectin by β-elimination was studied by Renard et al., in Visser &Voragen, Pectins and Pectinases pp. 603-608 (1996) and Sajjaanantakul etal., J. Food Sci., 54: 1272-1277 (1989). Oxidative depolymerisation ofpolysaccharides was studied by Miller in Biochemical and BiophysicalResearch Communications Vol 141, pp. 238-244 (1986). Examples of thermaldepolymerisation studies are given in Merril and Weeks, J. Am. Chem.Soc., 67: 224 (1945), Mitchell et al. U.S. Pat. No. 5,498,702 (1996).Enzymatic depolymerisation of pectin by polygalacturonase, pectin lyaseor pectate lyase has been widely recommended for depolymerisation ofpectic substance both in plant material as well as in pectin extracts.

The depolymerised pectin may be prepared by the following generalprocedure. Pectin, for example a commercially available pectin, isdissolved in demineralised water at 85-90° C. to constitute a 5%solution. The pH of the solution is adjusted to 5.5 by addition of 20%sodium carbonate solution. The solution is kept at 80° C. for 2 to 8hours until the viscosity of the solution (measured at 25° C.) islowered to 30 to 50 cP. The pH is subsequently lowered to 3.5 byaddition of 30% nitric acid and the mixture is cooled to roomtemperature. Pectin is precipitated out of the solution by pouring themixture in 3 volume parts 80% isopropyl alcohol under good agitation.After approximately four hours the precipitate is separated from theliquid by filtration through a cloth and washed with another part of 80%isopropyl alcohol. After pressing in the cloth the material is dried ina ventilated oven at 60° C. during the night. Finally the dried productis milled to obtain depolymerised pectin.

The stabiliser comprising depolymerised pectin may be provided in anysuitable form, in particular as a dry mix, as a solution or as adispersion. As previously mentioned, step (i) of the process iscontacting a food material with a stabiliser. This may be done in anysuitable manner. In one aspect, the stabiliser is dry mixed with sugarand then dissolved in water to provide a stabiliser solution. Thestabiliser solution is then mixed with a food material such as milk withstirring to provide the food intermediate.

In addition to the depolymerised pectin, the stabiliser may compriseother components such as dextrose. In one embodiment, the stabilisercomprises a depolymerised pectin and a high molecular weight high esterpectin.

The term “high molecular weight, high ester pectin” means a pectinhaving a viscosity in a 5% solution at 25° C. of more than 400 cP and adegree of esterification of at least 50%.

In one embodiment the stabiliser comprises essentially only adepolymerised pectin.

In another embodiment the stabiliser comprises at least onedepolymerised pectin.

In one preferred embodiment of the invention, the stabiliser is in theform of a blend. For example, the stabiliser may comprise two or moredepolymerised pectins, or a mixture of one or more depolymerised pectinsand one or more high molecular weight (HMW) pectins.

Thus, the stabiliser may comprise a blend of two or more depolymerisedpectins selected from the following:

-   -   HE depolymerised pectin;    -   LE depolymerised pectin;    -   amidated HE depolymerised pectin;    -   amidated LE depolymerised pectin;        which may be optionally combined with one or more high molecular        weight pectins.

In one particularly preferred embodiment, the stabiliser comprises amixture of two or more depolymerised pectins, i.e. the stabiliser is ablend of two or more different depolymerised pectins.

In one particularly preferred embodiment, the stabiliser comprises a LEdepolymerised pectin and a HE depolymerised pectin, wherein the LEdepolymerised pectin and HE depolymerised pectin are as definedhereinabove.

In another particularly preferred embodiment, the stabiliser comprises aLE depolymerised pectin and a HE depolymerised pectin in a ratio ofabout 10:1 to 1:10, more preferably about 5:1 to 1:5, more preferablystill about 3:1 to 1:3, more preferably still about 2:1 to 1:2.

In one especially preferred embodiment, the stabiliser comprises a LEdepolymerised pectin and a HE depolymerised pectin in a ratio of about1:1.

In another especially preferred embodiment, the stabiliser comprises aLE depolymerised pectin and a HE depolymerised pectin in a ratio ofabout 2:1.

In one particularly preferred embodiment, the stabiliser comprises about64% LE depolymerised pectin and about 36% HE depolymerised pectin.

As mentioned above, the one or more depolymerised pectins of theinvention may be combined with a high molecular weight pectin. Thus, inone preferred embodiment, the stabiliser comprises a LE depolymerisedpectin and a HMW pectin. In an alternative preferred embodiment, thestabiliser comprises a HE depolymerised pectin and a HMW pectin.

The HMW pectin (for use in combination with the depolymerised pectin)for use in the processes of the invention, for example in thestabilisation of drinking yoghurt, can be selected from a HMW pectinwith a degree of esterification from 60-85% and preferably from 65-75%.In order to prevent the problems associated with the use of high dosagesof HMW pectin in preparation of fermented protein foods, the dosage ofHMW pectin used in combination with the depolymerised pectin ispreferably lower than 0.15%, 0.1%, 0.75%, or 0.5%, and/or the ratio ofHMW to depolymerised pectin used in the process of the invention, shouldpreferably not exceed 50%, more preferably not exceed 40%, and morepreferably still not exceed 30%. More preferably, the dosage of HMWpectin used in combination with the depolymerised pectin is lower than0.15%.

In one particularly preferred embodiment, the ratio of HMW pectin todepolymerised pectin is about 30%. Such blends are observed to beparticularly advantageous.

Suitable HMW pectins for use in the processes of the present inventioninclude, but are not limited to the following:

-   -   GRINDSTED Pectin AMD 760, 780, 781, 782, 783, 382, 383    -   GRINDSTED Pectin RS 400, 450, 461    -   Unipectine AYD 10, 20, 22, 28, 29, 258, 30, 31, 35, 250, 358    -   Citrico type 7010, 7016, 7017, 7050, 7051, 7052, 7060, 7062,        7063    -   Classic CM 201, 203    -   Genupectin YM 100, 200, 115L, 115H, 150L, 150H; JM 150, 240; JMJ    -   Obipektin Brown Ribbon, Brown Ribbon K, Brown Ribbon P, Brown        Ribbon Q

In yet another preferred embodiment of the invention, the stabilisercomprises a LE depolymerised pectin and a HE depolymerised pectin, eachof which may be optionally amidated.

In one preferred embodiment, the stabiliser comprises an amidated LEdepolymerised pectin and a HE depolymerised pectin. More preferably, thestabiliser comprises an amidated LE depolymerised pectin and a HEdepolymerised pectin in a ratio of about 10:1 to 1:10, more preferablyabout 5:1 to 1:5, more preferably still about 3:1 to 1:3, morepreferably still about 2:1 to 1:2. More preferably still, the stabilisercomprises about 64% of an amidated LE depolymerised pectin and about 32%of a HE depolymerised pectin.

In another preferred embodiment, the stabiliser comprises a LEdepolymerised pectin and an amidated HE depolymerised pectin.

In yet another preferred embodiment, the stabiliser comprises anamidated LE depolymerised pectin and an amidated HE depolymerisedpectin.

In another preferred embodiment, the stabiliser comprises an amidateddepolymerised pectin and a HMW pectin.

Thus, in one preferred embodiment, the stabiliser comprises an amidatedLE depolymerised pectin and a HMW pectin. In another preferredembodiment, the stabiliser comprises an amidated HE depolymerised pectinand a HMW pectin.

The exact dosage of depolymerised pectin used in the invention isdependant on the viscosity and the type of depolymerised pectin used,and whether a mixture of LE/HE and/or amidated types of depolymerisedpectin are used, and whether the depolymerised pectin or mixture thereofis used in conjunction with a suitable dosage of a HMW pectin. Differentdepolymerised pectins, or mixtures thereof, or blends thereof with HMWpectin, may be preferred for different food products; for example, LEdepolymerised pectin, or a blend of LE and HE depolymerised pectin ispreferred in stirred yoghurt, whereas HE depolymerised pectin ispreferred for use in drinking yoghurt. This is further illustrated inthe accompanying examples. The optimum dosage of depolymerised pectinused can be readily determined by the person of ordinary skill in theart by routine experimentation using the methods set herein.

Typically, depolymerised pectin of higher viscosity, within the range ofthe invention, can be used at a lower dosage whilst still achieving thetechnical effects beneficial to the methods of the invention. The dosagemay also be dependent on the degree of esterification, although thiswill also depend on whether a pure depolymerised pectin or blend ofdepolymerised pectins is used. Typically depolymerised pectin with ahigher esterification value can be used at a higher dosage whilst stillachieving the technical effects beneficial to the methods of theinvention. As mentioned above, it is possible to use an amidateddepolymerised pectin in the invention. When using an amidateddepolymerised pectin the degree of esterification can be lower, whilstretaining the dosage levels obtained whilst using a depolymerised pectinwith a higher degree of esterification.

Food Material

As previously mentioned the food material comprises a protein.Preferably the protein is of animal, and/or vegetable, and/or microbialorigin. The protein may have been isolated from a suitable source, forexample as a protein powder or protein isolate.

A suitable food material comprising protein of animal origin may be, forexample, cows' milk, buffalo milk, goat milk or sheep milk. A suitablefood material comprising protein of vegetable origin may be or may bederived from, for example soy, rice, wheat, oat, pea or coconut.

In a preferred aspect, the food material comprises protein of animalorigin and protein of vegetable origin. Preferably, the food materialcomprises protein of animal origin. Preferably the protein is a milkprotein.

In one preferred aspect the food material comprises milk. In one aspectthe milk is selected from the list consisting of cows' milk, buffalomilk, goat milk and sheep milk. The milk may be whole fat milk or apartially defatted milk. In one aspect the food material comprises milkand a protein of vegetable origin. The protein of vegetable origin couldbe, for example, soya protein or rice protein.

Preferably, the milk has milk solid non-fat content of 0.1 to 25 wt %,preferably 3 to 25 wt %, more preferably 9 to 25 wt %.

The food material may comprise other food ingredients such asemulsifiers, hydrocolloids, preservatives, antioxidants, colourings,flavourings, acidulants and sweeteners.

Pre-Fermentation Pasteurisation

As previously mentioned, in one aspect, the process of the presentinvention comprises the step of (i)(a) pasteurising the foodintermediate.

Preferably the pasteurising step (i)(a) takes place at a temperature ofat least 80° C., preferably at least 90° C. More preferably thepasteurising step (i)(a) takes place at a temperature of at least 95°C., such as 95° C. to 100° C. In one aspect, preferably the pasteurisingstep (i)(a) takes place at a temperature of about 95° C. In one aspect,preferably the pasteurising step (i)(a) takes place at a temperature ofat least 100° C.

Preferably the pasteurising step (i)(a) takes place over a period of 1to 20 minutes, preferably 5 to 15 minutes, such as about 10 minutes.

In a preferred aspect the pasteurising step (i)(a) takes place at atemperature of about 95° C. for about 10 minutes.

Inoculation

As previously mentioned, in one aspect, the process of the presentinvention comprises the step of (i)(b) inoculating the food material.

Preferably the inoculation step (i)(b) comprises the addition of a livefood-grade micro-organism. Preferably the live food-grade micro-organismis a live food-grade bacterium. Preferably the live food-grade bacteriumis capable of influencing the taste and/or aroma and/or texture of thefood product. In one aspect preferably the live food-grade bacterium iscapable of influencing the taste of the food product. In another aspectpreferably the live food-grade bacterium is capable of influencing thearoma of the food product. In a further aspect preferably the livefood-grade bacterium is capable of influencing the texture of the foodproduct. Preferably the live food-grade bacterium is capable ofinfluencing the taste, aroma and texture of the food product.

The term “capable of influencing the taste and/or aroma and/or texture”means capable of altering the taste and/or aroma and/or texture of thefood product as compared with the food product in the absence of thelive food-grade bacterium.

Preferably the live food-grade micro-organism is a probiotic bacterium.

The term “probiotic bacterium” means a bacterium that has a beneficialeffect on human and/or animal health. A probiotic bacterium may act inthe gastrointestinal tract and/or in the urogenital tract. The healthbenefits of the probiotic bacterium may include:

-   -   antagonistic effects on pathogenic bacteria    -   beneficial metabolic activities such as production of vitamins        or bile salt hydrolase activity    -   stimulation of the immune response    -   protection against early events in carcinogenesis    -   improved recovery from intestinal disorders

In a preferred aspect, the live food grade micro-organism is selectedfrom the list consisting of Bifidobacteria, Streptococcus thermophilus,Lactobacilli and mixtures thereof. Preferably the live food grademicro-organism is selected from the list consisting of Bifidobacteria,Streptococcus thermophilus, Lactobacillus casei, Lactobacillusrhamnosus, Lactobacillus bulgaricus and mixtures thereof. In a preferredaspect, the live food-grade micro-organism comprises Lactobacillusbulgaricus and/or Streptococcus thermophilus, preferably Lactobacillusbulgaricus and Streptococcus thermophilus.

Preferably the live food-grade micro-organism is added in an amount of0.01 to 0.05 wt % of the food intermediate. Preferably the livefood-grade micro-organism is added in an amount of 0.01 to 0.03 wt %.

Fermentation

As previously mentioned, the process of the present invention comprisesthe step of (ii) fermenting the food intermediate.

Preferably the fermentation step (ii) takes place at a temperature offrom 30 to 50° C., preferably 35 to 45° C., more preferably 37 to 43° C.

In a preferred aspect, the fermentation step (ii) takes place at atemperature of about 42° C.

Preferably the fermentation step (ii) takes place over a period of 2 to48 hours.

In a preferred aspect, the fermentation step (ii) takes place at atemperature of about 42° C. over a period of 2 to 10 hours, preferably 4to 8 hours.

Post-Fermentation Pasteurisation

As previously mentioned, in one preferred aspect, the process of thepresent invention further comprises the step of (iii) pasteurising theproduct of step (ii).

Preferably the pasteurising step (iii) takes place at a temperature ofat least 80° C., preferably at least 85° C. More preferably thepasteurising step (iii) takes place at a temperature of at least 90° C.,such as 90° C. to 100° C. In one aspect, preferably the pasteurisingstep (iii) takes place at a temperature of about 90° C. In anotheraspect, preferably the pasteurising step (iii) takes place at atemperature of above 100° C.

Preferably the pasteurising step (iii) takes place over a period of 5 to30 seconds, preferably 10 to 20 seconds, more preferably about 15seconds.

In a preferred aspect, the pasteurising step (iii) takes place at atemperature of about 90° C. over a period of about 15 seconds.

This final post-fermentation pasturisation step may be included toprovide a long shelf-life product. In a preferred aspect, the foodproduct has a shelf-life of more than seven days, preferably more than14 days, more preferably more than 28 days. In one preferred aspect thefood product has a shelf-life of more than three months, preferably morethan four months, preferably more than five months, such as more thansix months.

pH Adjustment

As previously mentioned, in another preferred aspect, the processfurther comprises the step of (iv) adding juice and/or acid to theproduct of step (i)(b) and/or to the product of step (ii) and/or to theproduct of step (iii). Preferably the juice and/or acid is added to theproduct of step (ii) and/or to the product of step (iii). Preferably thejuice and/or acid is added to the product of step (ii).

Preferably the juice is a fruit juice. Examples of suitable fruit juicesinclude apple juice, apricot juice, banana juice, grapefruit juice,grape juice, guava juice, lemon juice, lime juice, mandarine juice,mango juice, orange juice, peach juice, pommelo juice, pumpkin juice,squash juice, tangarine juice, tomato juice and mixtures thereof.

The juice may be a natural or a treated juice (such as a concentratedjuice or a juice having one or more components separated therefrom.)Preferably the juice is pasteurised at a temperature of at least 80° C.,such as at least 85° C. or at least 95° C. prior to addition.

Preferably the acid is a food acid. Examples of suitable food acidsinclude citric acid, malic acid, and lactic acid. In this aspect,preferably the food acid is citric acid, lactic acid or a mixturethereof.

The addition of juice and/or acid may modify the pH of the system andtypically lowers the pH of the system.

In a preferred aspect the pH of the food intermediate immediately priorto the fermentation step (ii) is, or is adjusted to pH 6.0 to 8.0,preferably pH 6.3 to 7.0, such as pH 6.5 to 7.0, more preferably aboutpH 6.7.

In a preferred aspect, the juice and/or acid is added to the product ofthe fermentation step (ii). Preferably, sufficient juice and/or acid isadded to adjust the pH to less than pH 4.6, preferably less than pH 4.4,preferably less than pH 4.2, more preferably about pH 4.0.

Food Product

In one aspect the present invention provides a food product obtained bythe process of the present invention. In another aspect the presentinvention provides a food product obtainable by the process of thepresent invention.

The food product obtainable, preferably obtained by the process of thepresent invention may be any suitable fermented protein-containing foodproduct.

Examples of suitable food products include cheese, quarg, sour cream,imitation sour cream (e.g. with vegetable oil), dessert cream, fermenteddessert products (such as set or stirred yoghurt desserts and yoghurtmousse), frozen fermented products (such as frozen yoghurt or frozen,fermented ice cream), lassi drink, ayran, laban, buttermilk, kefir drink(lactic acid and alcohol fermentation), liquid yoghurt (such as drinkingyoghurt), lactic acid bacteria beverages, blends of fermented proteinbeverages and juice, pulp, fruit etc. based on e.g. milk, whey and/orsoy (this could be yoghurt mixed with juice like a smoothie which is notthe same as a milk juice drink directly acidified by the juice),fortified drinks (such as calcium-fortified drinking yoghurt) andprotein enriched soft drinks. Other suitable food products include anyof the above listed food products which comprise soy protein in additionto or instead of milk protein.

Preferably the food product contains a live food-grade micro-organism inan amount of from 0.01 to 0.05 wt %, more preferably 0.01 to 0.03 wt %,preferably, 0.02 wt %.

Preferably the food product contains the stabiliser in an amount of 0.1to 5.0 wt %, preferably 0.2 to 4.0 wt %, preferably 0.3 to 3.0 wt %.

Preferably the food product contains the depolymerised pectin in anamount of 0.1 to 1.0 wt %, preferably 0.2 to 0.8 wt %, preferably 0.4 to0.7 wt %. In one aspect preferably the food product contains thedepolymerised pectin in an amount of no greater than 0.4 wt % such as0.4 wt % to 0.1 wt %, or 0.4 wt % to 0.2 wt % or 0.4 wt % to 0.3 wt %.

In one aspect the food product is a beverage.

Preferably the food product is a fermented milk drink, preferably ayoghurt drink, more preferably a drinking yoghurt drink.

The term “fermented milk drink” covers a food product produced by anykind of fermentation by any kind of organism.

In one particularly preferred embodiment of the invention, the foodproduct is a yoghurt drink.

The term “yoghurt drink” typically covers a milk product produced byfermentation by the combination of Lactobacillus bulgaricus andStreptococcus thermophilus. The term yoghurt drink includes diluted milkdrinks with a low MSNF content.

In another particularly preferred embodiment of the invention, the foodproduct is a drinking yoghurt drink.

The term “drinking yoghurt drink” typically covers a milk productproduced by fermentation by the combination of Lactobacillus bulgaricusand Streptococcus thermophilus. Drinking yoghurt drinks typically have amilk solid non-fat content of 8% or more. Furthermore, the live culturecount for drinking yoghurt drinks is typically at least 10⁶ cell formingunits (CFU).

Where the food product is a drinking yoghurt drink, preferably thestabiliser comprises a HE depolymerised pectin or a blend of adepolymerised pectin and a HMW pectin. Preferably, the stabilisercomprises a HE depolymerised pectin, or a blend of a HE depolymerisedpectin and a HMW pectin. Preferably, where the stabiliser is a blend,the ratio of HE depolymerised pectin to HMW pectin is as definedhereinabove.

For drinking yoghurt drink, in one particularly preferred embodiment,the stabiliser has a viscosity at 25° C. in a 5% solution of greaterthan 150 cP, more preferably from 150 to 400 cP, even more preferablyfrom 300 to 400 cP, more preferably still, about 400 cP. In anotherparticularly preferred embodiment, the stabiliser has a viscosity at 25°C. in a 5% solution of about 25 to 50 cP, more preferably about 40 cP.

For drinking yoghurt drink, preferably the stabiliser has a degree ofesterification of from 50 to 85%, more preferably from 56 to 75%, morepreferably still, at least 70%.

For drinking yoghurt drink, preferably the stabiliser is selected fromthose set forth in Examples 1 and 2, i.e. the stabiliser is selectedfrom DPP2, DPP4, or a mixture of DPP4 and a HMW pectin (e.g. GRINSTED®Pectin AMD 780).

For drinking yoghurt, preferably, the stabiliser comprises from 0.4 to0.7 wt % of the depolymerised pectin or blend thereof. In oneparticularly preferred embodiment the stabiliser comprises a blend ofabout 0.3 wt % DPP4 and about 0.1 wt % of a HMW pectin (e.g. GRINSTED®Pectin AMD 780). In another particularly preferred embodiment thestabiliser comprises about 0.4 wt % DPP4, or about 0.5% DPP2.

In another preferred embodiment of the invention, the food product isstirred yoghurt.

The term “yoghurt” typically covers a milk product produced byfermentation by the combination of Lactobacillus bulgaricus andStreptococcus thermophilus or any other appropriate combination ofmicroorganisms. Yoghurt is a well known and discribed product type, asfor example by Tamine & Robinson [26]. More precisely, a summary of theprior art concerning yoghurt is given in U.S. Pat. No. 4,289,789 [27].

The term “stirred yoghurt” specifically refers to a yoghurt productwhich sustains a mechanical treatment after fermentation, resulting in adestructuration and liquefaction of the coagulum formed under thefermentation stage. The mechanical treatment is typically but notexclusively obtained by stirring, pumping, filtrating or homogenisingthe yoghurt gel, or by mixing it with other ingredients. Stirredyoghurts typically but not exclusively have a milk solid non-fat contentof 9 to 15%.

Where the food product is stirred yoghurt, preferably the stabilisercomprises a LE depolymerised pectin, or a blend of LE depolymerisedpectin and a HE depolymerised pectin. More preferably, the stabilisercomprises a LE depolymerised pectin and a HE depolymerised pectin in theratios defined hereinabove. More preferably still, the stabilisercomprises a LE depolymerised pectin and a HE depolymerised pectin in aratio of about 64% to 36%.

For stirred yoghurt, in another embodiment, the stabiliser comprises aHE depolymerised pectin, or a blend of a HE depolymerised pectin and aLE amidated depolymerised pectin.

In one particularly preferred embodiment, where the food product isstirred yoghurt, the stabiliser is selected from those disclosed inExamples 3 and 4 set forth below, i.e. the stabiliser is selected fromDPP5, DPP6, DPP7. DPP8, DPP9 and DPP10.

Preferably, for stirred yoghurt, the stabiliser has a viscosity of about20 to 50 cP, more preferably about 40 cP, when measured at 25° C. in a5% solution.

For stirred yoghurt, in one particularly preferred embodiment, thestabiliser comprises a LE depolymerised pectin used in an amount of fromabout 0.1% to about 0.5 wt %, more preferably from about 0.2% to about0.5, more preferably still from about 0.3% to about 0.5%.

For stirred yoghurt, in another particularly preferred embodiment, thestabiliser comprises a HE depolymerised pectin used in an amount of fromabout 0.1% to about 0.5 wt %, more preferably from about 0.2% to about0.5, more preferably still from about 0.3% to about 0.5%.

For stirred yoghurt, in one especially preferred embodiment thestabiliser comprises a blend of about 64% LE depolymerised pectin andabout 36% HE depolymerised pectin. Preferably, for this embodiment, thestabiliser is used in an amount of from about 0.1% to about 0.5 wt %,more preferably from about 0.2% to about 0.5, more preferably still fromabout 0.3% to about 0.5%.

For stirred yoghurt, in another especially preferred embodiment thestabiliser comprises a blend of a LE amidated depolymerised pectin and aHE depolymerised pectin used in an amount of from about 0.1% to about0.5 wt %, more preferably from about 0.2% to about 0.5, more preferablystill from about 0.3% to about 0.5%. Preferably, the ratio of LEamidated depolymerised pectin to HE depolymerised pectin is about 64% to36%.

Preferably the food product has a pH of less than pH 4.6, preferablyless than pH 4.4, preferably less than pH 4.2, more preferably about pH4.0 or less.

Preferably, the food product has a milk solid non-fat (MSNF) content of0.1 to 20 wt %, preferably 1 to 15 wt %, more preferably 1 to 10 wt %.In one aspect, the MSNF content is less than 3 wt %. In a preferredaspect the MSNF content is at least 3 wt %. In a further preferredaspect, the MSNF content is at least 8 wt %.

Drinking yoghurts typically contain a minimum of 8% by weight of MSNF.Yoghurt drinks typically contain a minimum of 3% by weight of MSNF,whereas soft drinks, milk juice drinks and similar products typicallycontain less than 3% by weight of MSNF.

As previously mentioned, in a preferred aspect, the food product has ashelf-life of more than seven days, preferably more than 14 days, morepreferably more than 28 days. In one preferred aspect the food producthas a shelf-life of more than three months, preferably more than fourmonths, preferably more than five months, such as more than six months.

Other Aspects

In one aspect, the present invention provides a process for theproduction of a food product comprising the step of dissolving astabiliser directly in a food material wherein the stabiliser comprisesa depolymerised pectin and wherein the food material comprises aprotein.

In this aspect preferably the stabiliser is in a solid form. Thestabiliser may for example be in the form of a powder. The stabilisermay be in the form of a dry mix with sugar.

In this aspect preferably the food material comprises milk, morepreferably the food material is milk.

In this aspect, preferably the process is as described herein. In thisaspect, preferably the stabiliser is as described herein. In thisaspect, preferably the food material is as described herein. In thisaspect, preferably the process, the stabiliser and the food material areas described herein.

In one aspect the present invention provides use of a stabiliser forimproving the texture and/or viscosity (such as mouthfeel and/or otherorganoleptic properties) of a food product, wherein the stabilisercomprises a depolymerised pectin. In this aspect preferably thestabiliser further comprises a high molecular weight, high ester pectin.In this aspect, preferably the food product is not a beverage.

The term “high molecular weight, high ester pectin” means a pectinhaving a viscosity in a 5% solution at 25° C. of more than 400 cP and adegree of esterification of at least 50%.

In this aspect preferably the food product comprises the stabiliser inan amount of 0.1 to 1 wt %, preferably 0.2 to 0.7 wt %, more preferably0.2 to 0.5 wt %.

Aspects of the invention are defined in the appended claims.

The present invention will now be described in further detail in thefollowing examples.

EXAMPLES

The following abbreviations are used throughout the Examples section:

DPP depolymerised pectin; HE pectin high ester pectin; LE pectin lowester pectin; DE degree of esterification; MSNF milk solids non-fat; AMD780 GRINDSTED ® Pectin AMD 780; SSPS Soyafibe-S-DA 100; SY 200GRINDSTED ® Pectin SY 200; Wave 212 GRINDSTED ® Pectin Wave 212; SY 640GRINDSTED ® Pectin SY 640.Viscosity Determination

The viscosity was measured by the following method.

25.00 gram of stabiliser was dissolved in approx. 500 ml demineralisedwater at 80° C. in a tared beaker to prepare a 5% solution.

The stabiliser solution was cooled to 25° C. and pH was adjusted to3.5±0.2 by addition of 1 N hydrochloric acid or 20% sodium carbonatesolution.

The total weight of the solution was brought to 500.0 gram by dilutionwith demineralised water.

The viscosity was measured on a Brookfield Viscometer model DV-II withspindle No. 61 (Spindles No. 62 or 63 on case of higher viscosities) at25° C. at 60 rpm.)

PECTIN CONCENTRATION 5% Stabiliser Viscosity (cP) (Spindle No.) pH DPP235 (61) 3.7 Wave 212 242− (62) 3.4 SSPS  9.5− (61) 3.5 AMD780 more than1000 (63) 3.3

Wave 212, SSPS and AMD780 are comparative examples.

Determination of Degree of Esterification and Degree of Amidation

5 g of the pectin sample was weighed to the nearest 0.1 mg into a 250 mlbeaker and 105 ml of solvent added (a mixture of 100 ml 60% aqueousisopropyl alcohol and 5 ml conc. hydrochloric acid). The mixture wasstirred on a magnetic stirrer for 10 minutes and then filtered through adried and pre-weighed coarse glass filter funnel under vacuum. Theresidue was washed with six 15 ml portions of the solvent followed by60% aqueous isopropyl alcohol (6-8 portions of 20 ml) until the filtratewas free from chloride (tested with a solution of 1.7 g silver nitratein 100 ml of distilled water). Finally, the solid was washed withapprox. 30 ml of 100% isopropyl alcohol and dried for 2½ hours in anoven at 105° C. The product was cooled in a desiccator and weighed.

20.00 ml of 0.5 N sodium hydroxide was transferred using a 20 mlvolumetric pipette into a beaker and mixed with 20.00 ml of 0.5 Nhydrochloric acid, transferred using a 20 ml volumetric pipette. Twodrops of a solution of phenolphthalein (1 g of phenolphthalein dissolvedin 100 ml of 96% ethanol) indicator was added and the solution titratedwith 0.1 N sodium hydroxide. The volume V₀ ml was recorded.

Exactly one tenth of the washed and dried pectin was weighed into a 250ml Erlenmeyer flask and moistened with 2 ml 96% ethanol. The flask wasplaced on a magnetic stirrer and 100 ml of boiled and cooled deionisedwater slowly added, avoiding splashing. The flask was stoppered andstirred until all the pectin was completely dissolved. Five drops of thesolution of phenolphthalein was added and titrated with 0.1 N sodiumhydroxide. The volume was recorded as V₁ in ml. 20.00 ml of 0.5 N sodiumhydroxide was added and the flask stoppered and shaken vigorously. Thecontent was allowed to rest for 15 minutes in order to saponify theester groups. 20.00 ml 0.5 N hydrochloric acid was added and thesolution shaken until the pink colour disappears. Three drops of thesolution of phenolphthalein were added and the solution titrated with0.1 N sodium hydroxide until a faint pink colour was achieved. Thevolume of 0.1 N sodium hydroxide required was recorded as V₂ ml.

The solution was transferred from the titration quantitatively to a 250ml round bottom flask and assembled to a dropcollector connected to acondenser with tight connection to a receiver flask through an adapter(Kjeldahl distillation equipment). 20.00 ml of 0.1 N hydrochloric acidwas added to the receiver flask. 55±5 ml of 30% sodium hydroxidesolution was added to the round bottom flask and the mixture distilledslowly and approx. 120 ml collected. 3 drops of indicator solution (0.4g of methyl red and 0.6 g of bromcresol green dissolved in 1 l 96%ethanol) were added to the distillate and the solution titrated with 0.1N sodium hydroxide until the equivalence point (B recorded in ml).

To calculate the degree of esterification:

V₃ = 20.00 − B${\%{DE}} = {\frac{V_{2} - V_{0}}{V_{1} + V_{2} - V_{0} + V_{3}}*100.}$

Calculate the degree of amidation:

${\%{DA}} = {\frac{V_{3}}{V_{1} + V_{2} - V_{0} + V_{3}}*100}$

Example 1

Objective: To test the performance of a depolymerised pectin added tomilk prior to pasteurisation, inoculation and fermentation forproduction of drinking yoghurt.

Stabiliser

GRINDSTED® Pectin AMD1387 was dissolved in demineralised water at 85-90°C. to constitute a 5% solution. pH was adjusted to 5.5 by addition of20% sodium carbonate solution. The solution was kept at 80° C. for 8hours until the viscosity of the solution (measured at 25° C.) waslowered to approx 35 cP. Then pH was lowered to 3.5 by addition of 30%nitric acid and the mixture was cooled to room temperature. Pectin wasprecipitated out of the solution by pouring the mixture in 3 vol. parts80% isopropyl alcohol under good agitation. After approx. four hours theprecipitate was separated from the liquid by filtration through a clothand washed with another part of 80% isopropyl alcohol. After pressing inthe cloth the material was dried in a ventilated oven at 60° C. duringthe night. The dried product was milled to DPP2.

DPP2 Pectin raw material Citrus Degree of Esterification: 69.3%Viscosity, 5% solution at 25° C.: 34.3 cP

The depolymerised pectin having a viscosity of 34.3 cP (DPP2) was usedin the following example.

The following commericial stabilisers were also used as comparativeexamples: GRINDSTED® Pectin AMD 780 (AMD 780), GRINDSTED® Pectin Wave212 (Wave 212), and Soyafibe-S-DA 100 (soluble soybean polysaccharide,SSPS, produced by Fuji Oil Co., Ltd., Japan). GRINDSTED® products areavailable from Danisco A/S.

Recipe conditions: The final drinking yoghurt was characterised by amilk solid non-fat content (MSNF) of 8%, a sugar content of 8%, a fatcontent of 0.1%, and a pH of 4.0-4.1. The stabilisers were applied inthe following concentrations (% w/w of total drink composition):

DPP2 0.5% Wave 212: 0.5% AMD 780: 0.4% SSPS: 0.4% SSPS: 0.5%

Process conditions: Skimmed milk powder was hydrated for 30 minutes at50° C. Stabilisers were dry mixed with ⅛ of the total sugar amount anddissolved in deionised water at 80° C. Thereafter, the stabilisersolutions were cooled to 40° C. and added to recombined milk understirring for 5 minutes. The stabiliser-milk blends were pasteurised intank at 95° C. for 10 minutes, cooled to fermentation temperature of 42°C. and inoculated with 0.02% yoghurt culture Jo-mix NM 1-20. Thestabiliser-milk blends were fermented to pH 4.2 at 42° C., then theywere agitated to brake down the casein curd and cooled to 10° C.

The remaining sugar part was added to the drinking yoghurts. pH wasadjusted to 4.0 by addition of citric acid solution. At this stage thesamples were divided into two parts: Homogenisation withoutpost-pasteurisation and homogenisation combined withpost-pasteurisation. Homogenisation was carried out at 300 bar. Samplesto be pasteurised were preheated to 60° C. and homogenised at 300bar/60° C. and subsequently pasteurised at 90° C. for 15 seconds. Alldrinks were filled in bottles and stored under cold conditions.

Evaluation of samples: All samples were inspected visually 1 day afterproduction having been stored at 5° C. In addition, all samples wereinspected visually and analytically 5 days after production having beenstored at 5° C. Viscosity was measured at 10° C. with a BrookfieldViscometer model DVII equipped with spindle no. 61 and running at 30rpm. The reading was taken after 30 seconds. Sedimentation wasaccelerated by centrifugation at 2800 g for 20 min. in a HeraeusVarifuge 3.2 S and expressed as the ratio of sediment to total sample.The particle size was measured in a phosphate-citrate buffer at pH 4.0on a Malvern Mastersizer S.

Results—1 Day Post-Production

Non-Pasteurised Samples (without Final Pasteurisation to Prolong ShelfLife)

Sample Visual inspection DPP2, 0.5% Fine. No separation and nosedimentation. Wave 212, 0.5% Weak separation and sedimentation. AMD780, 0.4% Separation and sedimentation. SSPS, 0.4% Fine. No separationand no sedimentation. SSPS, 0.5% Fine. No separation and nosedimentation. No stabiliser Separation and sedimentation.Post-Pasteurised Samples (Final Pasteurisation to Prolong Shelf Life)

Sample Visual inspection DPP2, 0.5% Fine. No separation and nosedimentation. Wave 212, 0.5% Weak separation and sedimentation. AMD780, 0.4% Separation and sedimentation. SSPS, 0.4% Fine. No separationand no sedimentation. SSPS, 0.5% Fine. No separation and nosedimentation. No stabiliser Separation and sedimentation.Results—5 Days Post-ProductionNon-Pasteurised Samples (without Final Pasteurisation to Prolong ShelfLife)

Accelerated Mean particle Sample pH Visual inspection sedimentationViscosity diameter DPP2, 0.5% 4.0 Weak separation and 13% 6 cP 2.7 μmsedimentation Wave 212, 0.5% n.a. Heavy separation and n.a. n.a. n.a.sedimentation AMD 780, 0.4% n.a. Heavy separation and n.a. n.a. n.a.sedimentation SSPS, 0.4% 4.1 Weak separation and 10% 3 cP 2.3 μmsedimentation SSPS, 0.5% 4.1 Weak separation and 13% 6 cP 2.6 μmsedimentation No stabiliser 4.0 Heavy separation and 18% 6 cP 6.0 μmsedimentationPost-Pasteurised Samples (Final Pasteurisation to Prolong Shelf Life)

Accelerated Mean particle Sample pH Visual inspection sedimentationViscosity diameter DPP2, 0.5% 4.0 Weak separation and 10% 6 cP 2.4 μmsedimentation Wave 212, 0.5% n.a. Heavy separation and n.a. n.a. n.a.sedimentation AMD 780, 0.4% n.a. Heavy separation and n.a. n.a. n.a.sedimentation SSPS, 0.4% 4.0 Weak separation and 10% 2 cP 2.2 μmsedimentation SSPS, 0.5% 4.1 Weak separation and 10% 5 cP 2.0 μmsedimentation No stabiliser 4.0 Heavy separation and 20% 7 cP 8.8 μmsedimentation

The samples containing Wave 212 and AMD 780 were separated totally withrather compact sedimentation. As it was impossible to re-disperse thissediment upon heavy shaking, it was not possible to characterise thedrinks with these stabilisers analytically.

AMD 780 was included in the application trial to illustrate whatgenerally happens when commercial pectin stabilisers are added to theapplication prior to fermentation. The pasteurised milk-pectin blenddestabilised almost immediately and did not re-stabilise under thefollowing processing of fermentation, homogenisation and pasteurisation.

Wave 212 is a HE pectin fibre product with characteristics similar toDPP2 despite the fact that it has a higher viscosity of around 242 cP ina 5% solution at 25° C. AMD 780 typically has viscosity of more than1000 cP. From other test series (not reported here) it is known thatWave 212 can stabilise the above drinking yoghurt recipe, when it isapplied at 0.5% to the fermented yoghurt. However, the present trialindicates that the viscosity is too high for Wave 212 to be added tomilk prior to fermentation without subsequent destabilisation of themilk-pectin blend.

SSPS is claimed to stabilise drinking yoghurt even when added to milkprior to pasteurisation, inoculation and fermentation. However, SSPS ismainly targeted at lower MSNF-contents and pH values than the appliedconditions in this trial. Therefore, the characteristics of the drinkingyoghurt in the present test are not quite optimal with SSPS—sedimentvalues of around 2-3% would be expected with the present recipe andprocess when stabilised with AMD 780 at normal conditions (i.e. addedafter fermentation to the yoghurt).

DPP2 demonstrates that a stabiliser comprising a depolymerised pectincan be added to milk prior to pasteurisation, inoculation, andfermentation of the milk with a stabilising performance comparable toSSPS. The milk-stabiliser blend did not separate upon pasteurisation,inoculation, and fermentation and a fairly stable product was obtainedupon homogenisation and even pasteurisation of the final drinkingyoghurt. Like for SSPS, the stability of the resulting drinking yoghurtsamples may not be fully optimal. Adjustment of recipe conditions (e.g.lower MSNF-content, lower pH) may improve the performance of DPP2.

The data illustrates that there is no detrimental effects of the secondpasturisation step—and hence the invention is suitable for applicationin long-life products (typically of 6 month shelf life), and to foodproducts containing live micro-organisms (typically 14 to 28 days shelflife).

Example 2

Objective: To test the performance of 1) DPP4 with a viscosity close to400 cP, and 2) the combination of DPP4 and high molecular weight pectinin a drinking yoghurt application where the pectin stabiliser is addedto milk prior to pasteurisation, inoculation and fermentation forproduction of long life drinking yoghurt (post pasteurised drinkingyoghurt).

DPP4 was made from GRINDSTED® Pectin AMD 1387 by the same procedure asDPP2, but only heat-treated for 2 hours to increase the viscosity at 5%solution to approx. 400 cP.

The characteristics of the depolymerised pectin sample tested were asfollows:

DPP4 Degree of esterification 70.4% Viscosity, 5% solution at 25° C. 387cP

The depolymerised pectin sample listed above (DPP4) was applied atdosages of 0.30% and 0.40%. In addition, a blend of 0.30% DPP4 and 0.10%AMD 780 (see below) was applied in the trial.

The following known stabilisers were used as comparative examples:GRINDSTED® Pectin AMD 780 (AMD 780) available from Danisco A/S wasapplied at 0.40%. Soyafibe-S-DA 100 (SSPS, soluble soybeanpolysaccharide, produced by Fuji Oil Co., Ltd., Japan) applied at 0.40%.

Drinking yoghurt model: The final drinking yoghurt was characterised bya milk solid non-fat content (MSNF) of 8%, a sugar content of 8%, a fatcontent of 0.1%, and a pH of 4.0. The milk base was fermented withJo-Mix NM 1-20.

Recipe and process conditions: (based on a total volume of 4000 g persample of drinking yoghurt) 337 g skimmed milk powder was hydrated for30 minutes at 50° C. in about 2830 g of water (ranging from 2826-2842depending on the stabiliser dosage). The stabilisers were dry mixed with⅛ of the total sugar amount and dissolved in 500 g of deionised water at80° C. Thereafter, the stabiliser solutions were cooled to 40° C. andadded to the recombined milk under stirring for 5 minutes. Thestabiliser-milk blends were pasteurised in a tank at 95° C. for 10minutes, cooled to a fermentation temperature of 42° C. and inoculatedwith 0.02% Jo-Mix NM 1-20. The stabiliser-milk blends were fermented topH 4.2 at 42° C. The blends were then agitated to break the casein curdand cooled to 10° C. to prevent post fermentation.

The remaining sugar part (320 g in total) was added to the drinkingyoghurts. PH was adjusted to 4.0 by the addition of citric acidsolution. The samples were homogenised at 300 bar/60° C. and subsequentpasteurised at 90° C. for 15 seconds. All drinks were cooled to 10° C.,filled in bottles and stored at cold conditions.

Evaluation of samples: All samples were inspected visually andanalytically seven days after production (stored at 5° C.). Viscosity ofthe final drinks was measured at 10° C. with a Brookfield Viscometermodel DV-II equipped with spindle no. 61 and running at 30 rpm. Thereading was taken after 30 seconds. Sedimentation was accelerated bycentrifugation at 2800 g for 20 min. at room temperature in a HeraeusVarifuge 3.2 S and expressed as the weight ratio of sediment to totalsample.

Results—7 Days Post Production

Accelerated sedimen- Sample pH Visual inspection tation Viscosity 0.30%DPP4 4.0 Heavy separation and 18% 7 cP sedimentation 0.40% DPP4 4.0 Weakseparation and 10% 5 cP sedimentation 0.30% DPP4 + 4.0 Weak separationand  7% 5 cP 0.10% AMD 780 sedimentation 0.40% SSPS 4.0 Weak separationand  7% 4 cP sedimentation Blind sample, 4.0 Heavy separation and 21% 10cP  i.e. no sedimentation stabiliser added

Compared to Example 1 above, this experiment applied a depolymerisedpectin sample having a higher viscosity, i.e. close to 400 cP (i.e. ahigher molecular weight than in the first trial). DPP4 sample wasapplied at lower dosages than in Example 1. A significant improvement ofstability compared to the blind sample was obtained with a dosage of0.40% DPP.

The stability was improved further by blending DPP4 and AMD 780. A blendof 0.30% DPP4 and 0.10% AMD 780 performed equally as well as 0.40% SSPSunder these conditions.

DPP4, which has a viscosity slightly lower than 400 cP, improved thestability of a post pasteurised drinking yoghurt when added at 0.40% tomilk prior to pasteurisation, inoculation, fermentation and postpasteurisation. The stability was improved further with a blend of 0.30%DPP4 and 0.10% AMD 780, where the stability equalled that obtained with0.40% SSPS.

Example 3

Objective: To test the performance of depolymerised pectin withdifferent degrees of esterification in a stirred yoghurt applicationwhere the pectin stabiliser is dry-blended with milk powder, dispersedand hydrated prior to pasteurisation, inoculation and fermentation forproduction of stirred yoghurt. The experiment also investigates whetherit is possible to achieve increased viscosity and enhanced creaminesscompared to that obtainable with a standard, high molecular weightproduct such as GRINDSTED® Pectin SY 200 dosed at its maximal acceptablelevel of 0.15% added to milk prior to fermentation.

225 g GRINDSTED® Pectin LC 1700 was dissolved in 4 L hot demineralisedwater and the temperature adjusted to 80° C. Then 1.2 g aqueous hydrogenperoxide solution (35%) was then added. After stirring for 4 hours at80° C. the mixture was cooled to room temperature and precipitated bymixing into 8 L 80 weight % aqueous isopropyl alcohol. After slowlymixing for an hour the precipitate was collected by filtration through acloth and the material further washed by suspension in 4 L 60 weight %aqueous isopropyl alcohol for one hour. After separation of the liquidphase by filtration through a cloth the precipitated material waspressed by hand and dried in a ventilated oven at 60° C. overnight. 203g dried DPP5 was milled to pass a 0.25 mm screen.

DPP7 was made from GRINDSTED® Pectin AMD 1387 by repetition of theprocedure for preparation of DPP2 in Example 1.

The characteristics of the depolymerised pectin samples tested and theapplied dosages were as follows:

GRINDSTED ® Pectin DPP 5 DPP 6* DPP 7 SY 200 Degree of 49.7% 56.7% 72.3% 49% esterification Viscosity, 5% 38.6 cP 38.9 cP 38.6 cP Higher than1000 cP solution at 25° C. Applied dosages 0.10% 0.10% 0.10% 0.15% 0.20%0.20% 0.20% 0.30% 0.30% 0.30% 0.40% 0.40% 0.40% 0.50% *DPP6 is a blendof 64% DPP5 and 36% DPP7, i.e. a blend of LE-DPP and HE-DPP pectins.

The commercial, standard pectin GRINDSTED® Pectin SY 200 (high molecularweight pectin) was used as a control for comparative purposes. This wasapplied as a reference at 0.15% corresponding to the maximal acceptablelevel before yoghurt becomes unacceptably grainy at the given processingconditions.

Stirred yoghurt model: The stirred yoghurt contained 2%-fat issued fromreconstituted skimmed milk powder and whole milk powder adjusted to 4.0%protein that corresponded to 10.5% MSNF. Fermentation was performed withYO-MIX™ 301 culture to a final pH target of 4.5.

Recipe and process conditions (based on a total volume of 4000 g persample of stirred yoghurt): Pectin was dry-blended with 225 g skimmedmilk powder and 294 g whole milk powder and added to 3468 g water at 45°C. under good stirring. The mix was homogenised at 65° C./200, preheatedto 80° C. and pasteurised at 95° C. for 6 minutes. The mix wasinoculated with 0.02% YO-MIX™ 301 and fermented at 42° C. to pH 4.5.Finally, the yoghurt sample was cooled to 24° C., filled and stored at5° C.

Evaluation of samples: All samples were analysed for the followingcriteria 3 days upon production:

-   -   pH was measured with a pH meter METTLER DELTA 340.    -   Brookfield viscosity was measured on a Brookfield DV        II+Viscometer running at rpm equipped with spindle S25. A sample        volume of 15 ml at 5° C. was used for the measurement. The        reading was taken after 30 seconds.    -   Visual syneresis on a scale from 1 (no whey at surface) to 9        (pronounced whey at surface).    -   Visual smoothness on a scale from 1 (high graininess) to 9 (high        smoothness).    -   Thickness judged as the resistance of the sample to disintegrate        in the mouth on a scale from 1 (very thin) to 9 (very thick).    -   Sandiness judged as remaining, perceived particles in the mouth        upon swallowing on a scale from 1 (smooth/no particles) to 9        (very sandy).    -   Creaminess in mouth judged as yes (creamy perception) or no        (watery).        Results—3 Days Post Production

Dosage Brookfield Visual Sample % pH viscosity, cP syneresis SmoothnessThickness Sandiness Creaminess DPP 5 0.10% 4.4 2000 2 8 5 3 No DPP 60.10% 4.4 2950 2 8 6 3 Yes DPP 7 0.10% 4.4 2750 2 8 6 3 Yes DPP 5 0.20%4.3 3350 2 8 7 3 Yes DPP 6 0.20% 4.4 2650 3 8 7 3 Yes DPP 7 0.20% 4.42700 3 8 7 3 Yes DPP 5 0.30% 4.5 2950 2 7 7 3 No DPP 6 0.30% 4.5 3350 27 8 3 Yes DPP 7 0.30% 4.5 3350 2 7 8 3 Yes DPP 5 0.40% 4.5 3300 2 7 8 3Yes DPP 6 0.40% 4.4 3800 2 7 8 3 Yes DPP 7 0.40% 4.4 3500 2 7 8 3 YesDPP 7 0.50% 4.5 3400 2 7 8 3 No SY 200 0.15% 4.4 2800 3 7 5 3 No

Viscosity: Except DPP5 dosed at 0.10%, all the depolymerised pectinsamples dosed at 0.10-0.20% yielded viscosities close to, equal to oreven slightly higher than 0.15% SY 200. Increasing the dosage ofdepolymerised pectin to 0.30% and above led to a clear improvement inthe viscosity compared to 0.15% SY 200.

Visual syneresis: All samples showed limited syneresis equivalent to thereference sample of 0.15% SY 200.

Smoothness: All samples were ranked high in smoothness with very smalldifferences.

Thickness: All samples were perceived as either equivalent or thickerthan the reference sample with 0.15% SY 200. As for the analyticallymeasured viscosity dosages of 0.30% and above, the depolymerised pectinsamples tested clearly improved thickness compared to 0.15% SY 200.

Sandiness: All samples were ranked equally in sandiness.

Creaminess: The reference sample with 0.15% SY 200 was not found creamy,whereas the depolymerised pectins tested made the stirred yoghurtcreamy.

With the depolymerised pectin samples applied in this trial (DPP5, DPP6and DPP7) it was possible to produce stirred yoghurt with viscositiesequivalent to or pronouncedly higher than obtained with the referencepectin GRINDSTED® Pectin SY 200 dosed at its maximal acceptable level of0.15%. Increased viscosity, enhanced sensory thickness and creamyperception were achieved with the depolymerised pectins dosed at 0.30%and above. Contrary to traditional, commercial high molecular weightpectin types like GRINDSTED® Pectin SY 200, such high dosages ofdepolymerised pectin could be dry-blended, dispersed and hydrated withmilk powder prior to pasteurisation, inoculation and fermentation forproduction of stirred yoghurt. This was possible without creation ofgrittiness that usually happens with standard pectin products likeGRINDSTED® Pectin SY 200 dosed at 0.15-0.20%.

Example 4

Objective: To test the performance of amidated LE depolymerised pectin,HE depolymerised pectin, and a combination thereof, in stirred yoghurtwhen applied to milk prior to pasteurisation and fermentation.

230 g GRINDSTED® Pectin LA1490 was dissolved in 4 L hot demineralisedwater by stirring and the temperature of the mixture adjusted to 80° C.To the stirred mixture was added 1.20 g aqueous hydrogen peroxide (35%)and the stirring continued at 80° C. for 4 hours. After cooling to roomtemperature, the depolymerised pectin was precipitated by mixing into 8L 80 weight % aqueous isopropyl alcohol. After slowly mixing theprecipitate for an hour the precipitate was collected by filtrationthrough a cloth and the material further washed by suspension in 4 L 60weight % aqueous isopropyl alcohol for one hour. After separation of theliquid phase by filtration through a cloth the precipitated material waspressed by hand and dried in a ventilated oven at 60° C. overnight. 217g DPP9 was isolated and milled to pass a 0.25 mm screen.

DPP10 was prepared from GRINDSTED® Pectin AMD 1387 according to Example1.

The composition DPP 8 used in this example was as follows:

DPP9 32 g DPP10 18 g Total 50 g

The composition of the blend DPP8 was 64% depolymerised amidated lowester pectin and 36% depolymerised high-ester pectin.

The characteristics of the depolymerised pectin samples tested were asfollows:

Pectin DPP8 DPP9 DPP10 Degree of amidation 15.4%  23.1% — Degree ofesterification 41.6%  27.7% 69.5%  Viscosity, 5% solution at 25° C. 33.7cP 35.4 cP 33.6 cP Applied dosage 0.3% not used 0.3% 0.4% as single 0.4%0.5% pectin 0.5%

As a reference was used GRINDSTED® pectin SY 640 at a dosage of 0.1%.GRINDSTED® pectin SY 640 is an amidated low ester pectin

Procedure: The procedure for the preparation of yoghurt is identical toExample 3 except that cream was added to the recipe to adjust the fat to2%. The powder ingredients were mixed and the dry blend was added to thecream and water under agitation at 45° C., and subsequently preheated to65° C., homogenised at 65° C./200 bar and pasteurised 95° C. for 6minutes. After pasteurisation the mixture was cooled to 5° C. prior tothe addition of a starter culture Yo-Mix 410 (added as a 10% solution inskimmed milk 0.02 units/l). After innoculation of the starter culture,the milk preparation was fermented at a temperature of 42° C.

The fermentation was allowed to proceed to pH 4.50. The typicalfermentation time with the specific selected culture was found to beabout 5 hours. The ferment was cooled on plate heat exchanger to 24° C.and placed in 5×155 ml beaker of each and stored at 5° C.

The yoghurts produced were analysed for:

-   -   Syneresis, measured after 3 weeks;    -   Polyvisc viscosity: Polyvisc® equipment, measurement of distance        covered after 15 s by the release of a 100 ml volume of yoghurt        at 5° C.; a high Polyvisc index corresponds to a fluid, non        viscous product;    -   Brookfield viscosity (standard)

The characteristics of the depolymerised pectin samples tested were asfollows:

Composition of Yoghurt Trials:

Pectin type none SY 640 DPP8 DPP 10 pectin dosing levels   0.0%;   0.1%;  0.3%;   0.3%;   0.0%;   0.1%;   0.4%;   0.4%;   0.0%  0.1%  0.5%  0.5%TOTAL FAT  2.000% 2.000% 2.000% 2.000% TOTAL MSNF 11.000% 9.800% 9.800%9.800% TOTAL DRY MATTER 18.000% 16.900%  17.100-  17.100-  17.300% 17.300%  TOTAL SUGAR 10.849% 10.211%  10.211%  10.211%  TOTAL PROTEIN 4.172% 3.718% 3.718% 3.718%Evaluation of Yoghurt Trials:

Syneresis Brookfield Brookfield [index Dosage 3 days* ± 3 weeks ±Polyvisc after 60 Sample % 350 [cP] 350 [cP] [mm/sec] min] Referencenone 4800 6300 38 100 11% MSNF Reference none 4200 4400 59 100 11% MSNFReference none 4200 3900 67 100 11% MSNF SY640 0.1 4950 — 59 99 SY6400.1 5750 — 45 93 SY640 0.1 5600 5300 50 80 DPP 8 0.3 5150 7500 48 95 DPP8 0.4 5500 6600 55 96 DPP 8 0.5 2200 2500 135 94 DPP 10 0.3 5650 6100 5785 DPP 10 0.4 5950 6000 62 89 DPP 10 0.5 6150 7500 43 67

The overall conclusion from this series of trials was that dosing levelsof 0.3% to 0.5% of DPP10 HE depolymerised pectins give similar or evenhigher viscosity levels than a dosing of 0.1% of the reference SY 640pectin or reference yoghurt without pectin with 11% MSNF+, as indicatedby high Brookfield viscosities and low Polyvisc index levels. The sameconclusion can be drawn for pectin DPP8 at dosing levels of 0.3% and0.4%, but at dosing level of 0.5%, viscosity in yoghurt samplecontaining pectin DPP8 collapses.

At all dosing levels, syneresis was lower in yoghurts samples containingany of the 3 tested pectins than in the reference 11% MSNF yoghurtsamples.

All publications mentioned in the above specification are hereinincorporated by reference. Various modifications and variations of thedescribed methods and system of the invention will be apparent to thoseskilled in the art without departing from the scope and spirit of theinvention. Although the invention has been described in connection withspecific preferred embodiments, it should be understood that theinvention as claimed should not be unduly limited to such specificembodiments. Indeed, various modifications of the described modes forcarrying out the invention which are obvious to those skilled inchemistry, biochemistry or related fields are intended to be within thescope of the following claims.

REFERENCES

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1. A process for the production of a fermented dairy product comprisingthe steps of: (i) contacting a food material with a stabiliser toprovide a food intermediate; (i)(a) pasteurising the food intermediate;(i)(b) inoculating the food intermediate; and (ii) fermenting the foodintermediate; wherein the stabiliser is present in an amount of 0.3 to3.0 wt %, and comprises a depolymerised pectin having a degree ofesterification of at least 50% wherein the food material comprises milk.2. A process according to claim 1 further comprising the step of (iii)pasteurising the product of step (ii).
 3. A process according to claim 1further comprising the step of (iv) adding juice and/or acid to theproduct of step (i)(b) and/or to the product of step (ii) and/or to theproduct of step (iii).
 4. A process according to claim 1 wherein thedepolymerised pectin has a viscosity at 25° C. in a 5% solution of 15 cPto 400 cP.
 5. A process according to claim 1 wherein the depolymerisedpectin has a viscosity at 25° C. in a 5% solution of 20 cP to 200 cP. 6.A process according to claim 1 wherein the depolymerised pectin has aviscosity at 25° C. in a 5% solution of 25 cP to 50 cP.
 7. A processaccording to claim 1 wherein the depolymerised pectin is an essentiallylinear carbohydrate polymer.
 8. A process according to claim 1 whereinthe depolymerised pectin has a galacturonic acid content of at least65%.
 9. A process according to claim 1 wherein the depolymerised pectinhas a degree of esterification of from 50 to 85%.
 10. A processaccording to claim 1 wherein the depolymerised pectin has a degree ofesterification of from 65 to 75%.
 11. A process according to claim 1wherein the food material further comprises a protein of vegetableand/or microbial origin.
 12. A process according to claim 1 wherein themilk has a milk solid non-fat content of 0.1 to 25 wt %.
 13. A processaccording to claim 1 wherein the milk is whole fat milk or partiallydefatted milk.
 14. A process according to claim 1 wherein thefermentation step (ii) takes place at a temperature of from 30 to 50° C.15. A process according to claim 1 wherein the fermentation step (ii)takes place over a period of 2 to 48 hours.
 16. A process according toclaim 2 wherein the pasteurising step (iii) takes place at a temperatureof at least 80° C.
 17. A process according to claim 2 wherein thepasteurising step (iii) takes place over a period of 5 to 30 seconds.18. A process according to claim 1 wherein the fermented dairy productis a beverage.
 19. A process according to claim 1 wherein the fermenteddairy product is a fermented milk drink.
 20. A process according toclaim 1 wherein the fermented dairy product is a yoghurt drink.
 21. Aprocess according to claim 1 wherein the fermented dairy product is adrinking yoghurt drink.
 22. A process according to claim 1 wherein thefermented dairy product is a stirred yoghurt.
 23. A process according toclaim 1 wherein the fermented dairy product contains a live food-grademicro-organism in an amount of from 0.01 to 0.03 wt %.
 24. A processaccording to claim 1 wherein the fermented dairy product has a pH ofless than 4.6.
 25. A process according to claim 1 wherein thedepolymerised pectin is amidated.
 26. A process according to claim 1wherein the stabiliser is a blend of a HE depolymerised pectin and a LEdepolymerised pectin.
 27. A process according to claim 1 wherein thestabiliser is a blend of a LE amidated depolymerised pectin and a HEdepolymerised pectin.
 28. A process according to claim 1 wherein thestabiliser is a HE depolymerised pectin and a high molecular weightpectin.
 29. A process for improving the texture and/or viscosity of afermented dairy product, comprising including a stabiliser in saidfermented dairy product, wherein the stabiliser comprises adepolymerised pectin having a degree of esterification of at least 50%,and wherein said stabiliser is present in an amount of 0.3 to 3.0 wt %,and applied directly to the dairy product prior to fermentation.
 30. Theprocess according to claim 29 wherein the high molecular weight pectinis a high ester pectin.